1. Technical Field
The present invention relates generally to a MEMS device, and more particularly, to a micro-scale positioning device capable of rapidly scanning a stage portion relative to a ground or target with a relatively high degree of accuracy and precision.
2. Background Information
Throughout this application, various publications, patents and published patent applications are referred to by an identifying citation. The disclosures of the publications, patents and published patent applications referenced in this application are hereby incorporated by reference into the present disclosure.
There is a growing need for high-bandwidth (high speed), fine motion control and positioning at micro- and nano-scales, such as for a growing number of MEMS applications, including optical switching, active alignment of fiber optic elements, micro-scale machining, micro-resonators, manipulation for bio molecules, and micro-scanners for endoscopy and other medical scanning procedures.
Culpepper, in U.S. patent application Ser. No. 10/175,415, filed on Jun. 19, 2002, entitled “Six Degree of Freedom Flexure Stage”, (the ‘415 reference’), discloses an adjustable monolithic compliant mechanism. This compliant mechanism includes a stage which may be adjusted by displacing one or more tabs coupled thereto, to provide for controlled movement in six degrees of freedom.
Next generation applications (e.g., high speed fiber optic alignment, optical switching, and the like) will require precision alignment devices capable of being fabricated on a micro- or nano-scale, e.g., as MEMS devices fabricated on a chip-level using many conventional semiconductor fabrication techniques, and which are capable of providing high speed operation, with high resolution (i.e., nanometer/microradian) position control with up to six degrees of freedom (i.e., x, y, z, θx, θy, and θz).
However, many applications, even those that may not require movement in a full six degrees of freedom, require higher speed operation than that provided by conventional micro-actuators. For example, thermal actuators may be heated (and thus actuated in one direction) relatively quickly, but then return to their rest position relatively slowly (i.e., as a function of heat dissipation). This characteristic thus represents a limit to their speed of operation (bandwidth) and consequently, to the range of applications in which these actuators may be employed. This limitation similarly applies to nominally any other actuators (such as electro-mechanical and magnetostrictive actuators) that are moved upon an application of energy, and then rely on dissipation of that energy to return to a rest or neutral position.
Therefore there exists a need for a micro- and/or nano-fabricated, positioning device capable of high bandwidth operation.